The majority of researchers in the field of cosmogony, though not all of them, think that the Solar System had appeared 4 to 5 billion years ago and, since then, it has not undergone any considerable changes. They believe that Earth, like the other planets, was the same as now – both one, three and five billion years ago. The same was its mass, distance to the Sun, the inclination of the plane of Earth orbit to the plane of Sun equator, the slope of the plane of Earth equator to the plane of its orbit, periods of its axial rotation and orbital circulation, etc. The only change on Earth that can be called a radical one is the origin of life (biosphere), as well as the appearance of man and society (noosphere). Besides, there were some climatic changes, whether because of periodical changes of luminosity (radiating power) of the Sun, or as a result of passing the Solar System through gas-dust clouds and nebulas. As for other celestial bodies of the Solar System, they (as if) are in invariable, “preserved” state for several billion years. According to these concepts, the picture that can be seen on the surface of the Moon, Mercury or Mars today could also be seen there three or four billion years ago. These researchers are not influenced by the recently discovered facts that there are both old and more “young” rocks on the Moon, that there are dry river-beds on Mars, etc.; such a position points to inertness and even stagnation of thinking.

One of the main arguments for confirmation of such a dull picture is the fact that the fall of cosmic precipitations onto Earth surface is (as if) negligibly small: only several thousand tons a year, at best – several dozen thousand tons. We think that this point of view is utterly unfounded. In fact, what is it based on? On the fact that the amount of cosmic precipitations is small now? But, first, it became clear recently that this amount is not several thousand tons a year, but about three thousand tons a day, i.e. about one million tons a year or one trillion tons for one million years.

Second (and this is the main point), these figures tell nothing about the fall of cosmic precipitations one million or one hundred million years ago.

It is appropriate here to draw an analogy to atmospheric precipitations on Earth. Let’s make a small digression first. The earthly year is known to contain 365 days. The galactic year is “a little” longer: it is equal to 200 to 250 million earthly years.
The galactic year, like the earthly one, has its seasons: summer, autumn, winter and spring. Galactic winter for the Solar System begins when it, in the course of its circulation around the centre of Galaxy, crosses the galactic plane. It is known that the plane of Galaxy contains huge masses of diffuse matter: interstellar gas with 1 to 5% touch of cosmic dust consisting, apparently, mainly of silicate component. If all this diffuse matter is at a time turned to star-planet systems, similar to the Solar System, then billions and even dozens of billions of new systems would appear.

And this gas-dust plane of |Galaxy is being crossed by the Solar System twice during each galactic year: first time – when moving from northern hemisphere of Galaxy to southern one, second time – during reverse motion from southern to northern hemisphere. When the Solar System crosses the central plane of gas-dust disc of Galaxy that is saturated with gas and dust to the maximum, a galactic winter begins.

Thus, the Solar System goes through not one but two galactic winters during each galactic year; their duration is approximately equal to ten to fifteen million years.

So what happens when a galactic winter begins? First, the dust of diffuse matter screens sun rays, scattering some part of them into cosmic space. Second, a part of sun rays is being absorbed by diffuse matter of the galactic plane. As a result, a fall of temperature begins on the Earth; a regular ice age comes. Galactic winters, just like earthly ones, can be different by degree of temperature fall. The higher is the concentration of dust in the part of galactic plane being crossed by the Solar System, the more is temperature drop. If there is less dust, then the temperature drop is less significant. And if this part of galactic plane is completely free from dust; then there would be no temperature drop and ice age at all. And what is more, in the latter case, not drop but rise of temperature could take place as a result of chemical reaction of hydrogen, a great amount of which is available in the plane of Galaxy, with oxygen from Earth atmosphere. In the course of this reaction, water is being formed and a significant amount of heat is being generated. Moreover, water resources of Earth hydrosphere increase, so that the level of the world ocean gradually increases with every galactic winter.

If we remember how the fall of atmospheric precipitations in different places of Earth in one and the same time or in one and the same place during different seasons takes place, then it turns out that they fall very non-uniformly: now there is no rain in summer (or snow in winter) for many weeks, causing sometimes harvest loss, drying up rivers and reservoirs, etc., now, on the contrary, it pours day by day in summer (or it snows in winter), so that rivers overflow the banks, flood the fields and dwelling places.

Let’s imagine: two mosquitoes or some other insects, life duration of which amounts to several days, suddenly became intelligent (just like humans) and began to argue about atmospheric precipitations. If all their ten-day life falls on droughty period, then they would probably come to firm conclusion that there are no atmospheric precipitations on Earth as such. But if they are born and spend their lives during rainy period, they would think that atmospheric precipitation is an everyday phenomenon of Earth development.

Don’t you think that some scientists resemble these insects? After all, human life lasts only some 70 years, mankind exists for 2 or 3 million years, while the duration of galactic year is equal to 200 to 250 million earthly years. All the history of our civilizations is not more than a minute in comparison with galactic year.

The science tells us that ice ages repeat themselves periodically; it means that galactic winters do not pass without leaving a trace. But they do not only bring cold spells with them. Galactic winters also increase the fall of cosmic precipitations onto celestial bodies sharply. In these very periods, the fall of cosmic precipitations onto the surface of Earth and other bodies of the Solar System rise multiply. It is during galactic winters that the active geological life of the planets (volcanic activity, earthquakes, orogeny, etc.), as well as the Sun activity begins. But modern era is a period of quiet life of the Solar System, if you wish – summer hibernation.

Cosmic precipitations fall onto the planets and other bodies of the Solar System, first, by means of scooping the diffuse matter by the celestial bodies out of galactic plane during crossing the latter by the Solar System and, especially, in process of passing through the spiral branches of the Galaxy. Second, this takes place in the form of accretion (condensation) of diffuse matter onto the surface of celestial bodies; and, third, by means of falling solid celestial bodies: meteorites, comets, asteroids, satellites and planets.

The same cosmic precipitations fall onto the celestial bodies of the Solar System during galactic summer as well, but its amount cannot be compared with that falling in the course of galactic winter. One may suppose that the amount of precipitations during galactic winters increases several thousand times.

It should be noted that galactic winters, just like earthly ones, are different. During some galactic winters, the amount of cosmic precipitations is significant; during the others – it is small. It can be explained by the fact that sometimes, apparently, once in several billion years, the Solar System in the course of its circulation around the centre of Galaxy during a regular galactic winter passes through a spiral branch of Galaxy, the density of diffuse matter in which is several times (maybe, several dozen times) more than that in the plane of Galaxy on average. Such galactic winters are the most severe; in the course of them, the mass of celestial bodies increases especially quickly. If, during crossing the plane of Galaxy between spiral branches, the increase of masses of celestial bodies as a result of cosmic precipitations fall is equal, maybe, to some fractions of percent or, at best, several percent, then, during passing the Solar System through a spiral branch, especially in its central part, the masses of celestial bodies of the Solar System increases by tens and, maybe, hundreds percent. One could suppose that, during the last intersection of a spiral branch by the Solar System about 4 billion years ago, the mass of the Sun had increased to the extent that the Sun turned from a wan red or orange dwarf to a hot star of G2 spectral class. Life on the Earth appeared soon after tha.

It should also be noted that, together with two galactic winters setting in each galactic year in regular intervals, at certain time, sometimes an unexpected galactic winter comes. It happens when the Solar System meets one of the numerous gas-dust clouds that haven’t entered the plane of Galaxy (and then – a spiral branch) yet. Since these clouds are different by their size, density and chemistry, then the galactic winters coming “out of schedule” could be different: from short and mild to prolonged and severe ones. There may be no unexpected winters during a galactic year at all; in the course of another year, there may be several such winters.

The fact that the cosmic precipitations creating the ice component fall onto the surface of planets of the Solar System is eloquently testified by dry beds of giant rivers on the surface of Mars having been discovered recently. In process of concentration of diffuse matter, such ingredients of the latter as hydrogen and oxygen reacted with each other; as a result, a great amount of gaseous, liquid and solid water had formed on the surface of Mars, as well as other planets. At that, liquid water flew from higher places down to lower ones creating rivers and large reservoirs. On completion of a regular galactic winter (or, maybe, before its completion), liquid water flowing down the river-beds to reservoirs, vaporized and gradually entered Martian atmosphere, wherefrom it dissipated to interplanetary space in the form of water steam molecules and, especially, in the form of atoms of hydrogen and oxygen. Some part of water fell in polar and sub-polar regions of Mars in the form of atmospheric precipitations; a part of it is still there today. If we determine the age of rocks of the bottom of dry river-beds (i.e. the time of their deposition), then we could thereby fix the time of completion of the last galactic winter. However, the latter moment could also be determined another way. During intersection of the gas-dust plane of Galaxy, a great amount of various gases: hydrogen, helium, nitrogen, carbon dioxide, hydrogen sulfide, methane, ammonia, etc. Many of these gases are harmful for health and the very life of living organisms of Earth. As a result, a great number of animals and plants die. Many biological species become extinct. It is known that similar catastrophe in the life of Earth biosphere took place some 60 to 70 million years ago; in particular, all the dinosaurs of our planet died out in this very time. One might suppose that this was the time when the Solar System crossed the galactic plane with all the ensuing consequences.

At first glance, all the celestial bodies of the Solar System have different characteristics. However, they could be divided into three big groups. To the first of them, the most compact bodies of the Solar System (with the density of about 3 g/cm3 and more) could be related. Such are, first of all, terrestrial planets: Mercury, Venus, Earth and Mars. Some large satellites of planets: the Moon, Io, Europa and, apparently, Triton, as well as a number of small satellites circling not far from their planets – Phobos, Deymos, Amaltea, etc., belong to this group as well.

The fact that the most compact bodies of the Solar System circle near their central bodies is not accidental. First, the terrestrial planets are near the Sun that heats their surfaces thereby promoting dissipation of not only gaseous but also ice component from the surfaces and atmospheres of celestial bodies. Second, the dissipation of light substances is also contributed by transition of mechanical energy to thermal energy under the influence of tidal friction. And the tidal friction inside celestial bodies caused by their central bodies is stronger when they are closer. The fact that Io and Europa being the nearby satellites of Jupiter have the densities of 3.5 and 3.1 g/cm3 respectively, while the more distant though more massive Ganymede and Callisto have by far lower densities – 1.9 and 1.8 g/cm3 respectively, is in part explained by this very circumstance. The same is the reason of the fact that all the near satellites circulate around their planets synchronously, i.e. are always turned to them with one and the same side, so that their periods of axial rotation and orbital circulation are equal. However, the tidal friction, being conductive to heating the depths of celestial bodies and rise of their density, is being caused not only by central bodies to their satellites, but also in opposite direction, as well as between the celestial bodies belonging to the same class: by satellites to other (mainly neighbouring) satellites, by planets to other planets.

The celestial bodies of big density can be called silicate celestial bodies, bearing in mind that the main component of them is silicate component (stone and metallic rocks) consisting of the most heavy and refractory substances: silicon, calcium, iron, aluminium, magnesium, sulfur and many other elements and their compounds, including (and mainly) those with oxygen. Along with silicate component, many celestial bodies of this group have ice component (water ice, water, carbon dioxide, nitrogen, oxygen) and a very small gaseous component (hydrogen, helium). But the proportion of the last two components is insignificant. The silicate component contains, as a rule, more than 99% of substance of celestial body.

The group of silicate celestial bodies of the Solar System includes not only four planets and some dozen planet satellites, but also a great number of asteroids, circling the Sun in the asteroid belt between the orbits of Mars and Jupiter. The number of asteroids, the largest of which being Ceres, Pallada, Vesta, Gigea, etc., is estimated at dozens of thousand (according to some sources – at hundreds of thousand and even millions).

The second group of celestial bodies unites the ice bodies, the main part of which is ice component. This is the most numerous group of celestial bodies of the Solar System. It includes one known planet – Pluto, many trans-pluto planets that are not discovered so far, large satellites of planets: Ganymede, Callisto, Titan, Charon, and, apparently, some two or three dozen other satellites. This group also includes all the comets, the number of which in the Solar System amounts to many millions or, maybe, billions.

This group of celestial bodies is the main group of celestial bodies of the Solar System and, obviously, of the whole Galaxy. Many researchers think that there are planets behind Pluto. Undoubtedly, they are right. Ice celestial bodies are the most numerous and the main group of celestial bodies in the Solar System and, without a doubt, in all the other star-planet systems, both small and large.

The ice bodies of the Solar System consist mainly of ice component: water ice, carbon dioxide, nitrogen, oxygen, ammonia, methane, etc., representing the main part of their substance. The remaining insignificant part of ice bodies is taken mainly by silicate component. The proportion of gaseous component in ice celestial bodies (like in silicate ones) is negligible that can be explained by their relatively small masses. For this reason, they cannot hold light gases – hydrogen and helium, near the surface for a long time; these gases dissipate into interplanetary space. This rule has an exception for the planets distant from the Sun, since the temperature on their surfaces is very low.

Small ice celestial bodies – comets are situated not only at the periphery of the Solar System, behind Pluto. A great number of them move, apparently, between the orbits of giant planets as well.

The third, the least numerous but the most massive group of bodies of the Solar System embraces the celestial bodies consisting of large three components: ice, silicate and gaseous. This group includes only the five celestial bodies of the Solar System: the Sun, Jupiter, Saturn, Uranus and Neptune. All of them contain a lot of hydrogen and helium, but their proportion in these bodies is different. In the course of creation of gaseous bodies (let’s call them so), the latter, having the mass of less than 10 Earth masses at the first stage of their development, could not hold light gases – hydrogen and helium near their surfaces and were formed initially as ice bodies. At that stage, they consisted of ice and silicate components. A considerable part of gas component, having acquired by gaseous celestial bodies during galactic winters, turned to ice component by means of chemical reactions. So, hydrogen and oxygen, as a result of chemical reaction, create water and water ice. Methane and some other substances of ice component had appeared from gaseous component. As a result, in the course of accretion of diffuse matter onto the surface of celestial bodies, the proportion of ice component increased, while the part of gaseous one reduced.

The giant planets, in contrast to the other celestial bodies, are characterized by quick axial rotation and extensive hydrogen-helium atmosphere. As a result, the leakage of light gases from upper layers of atmosphere to interplanetary space owing to large centrifugal forces is quite possible. For example, the upper layers of clouds of Saturn atmosphere rotate around the center of the planet at the linear speed of 10 km/sec; the similar characteristic for earthly atmosphere being only 0.5 km/sec. One might suppose that previously, during galactic winters, giant planets had much thicker and denser atmospheres; on completion of just another galactic winter they partly lost them. If ice and silicate celestial bodies lose their gaseous components because of small masses, then gaseous celestial bodies, especially Jupiter, lose it owing to their rapid rotation.

We have already said that masses and dimensions of celestial bodies grow in the course of time, but this growth is very irregular. During galactic summer, the increase of substance is very small. During galactic winter, it is the largest. At that, the celestial bodies grow by three different ways. First, as a result of fall of other, small bodies onto their surfaces. The surfaces of Moon, Mercury and Mars, as well as planet satellites, sown with big and small meteorite craters, eloquently testify that falls of the solid bodies onto the surface of celestial bodies of the Solar System are quite frequent phenomena. Second, the celestial bodies increase their dimensions and masses owing to scooping the diffuse matter, as well as its condensation (accretion) onto the surfaces of celestial bodies during the intersection of gas-dust galactic plane and the gas-dust clouds at the periphery of Galaxy. The gain of substance is the greatest, when the celestial bodies cross the spiral branches of Galaxy.

As a result, the masses and dimensions of all the celestial bodies of the Solar System (and of all the other star-planet systems) increase. But they increase differently. Some bodies of the Solar System grow slower, the others – quicker. The gaseous bodies, i.e. the Sun and giant planets, grow quicker than the others. We have already seen above that all the celestial bodies (both silicate, ice and gaseous ones) not only acquire substance, but simultaneously lose it. The Sun is not an exception in this respect. The point is that the mass of the Sun is constantly, though slowly, reducing at the expense of radiation. Although the lost of Sun mass during galactic winter is insignificant, the overall lost of mass during galactic year is very appreciable. Nevertheless, in the course of all the galactic year, the Sun acquires more mass owing to accretion of interstellar substance than it loses during the same period, so that both mass, dimensions, luminosity and temperature the Sun increase gradually. This growth is especially noticeable when the Solar System sinks into a spiral branch of Galaxy during regular galactic winter.

The ice bodies of Solar System grow slower than gaseous ones do. The giant planets and the Sun increase their masses and dimensions at the expense of addition of all three components of cosmic precipitations: gaseous, ice and silicate, while the ice bodies absorb only silicate and ice components. The gaseous component is being quickly lost by these bodies, with the exception of the part that is converted to ice component. This waste is explained by small masses and, consequently, gravitational forces of these bodies. Therefore, gases having fallen into their surface dissipate from it to interplanetary space, since the speed of atoms and molecules of gaseous component reaches the second cosmic speeds for the surfaces of ice celestial bodies of the Solar System.

Still slower is the growth of masses of silicate bodies of the Solar System, including the terrestrial planets, since they lose not only gaseous, but also ice (entirely or partially) component. Only the biggest of them: Earth, Venus and, apparently, Mars are able to hold some part of ice component at their surfaces.

Thus, the celestial bodies increase their masses and dimensions irregularly. The quickest is the growth of gaseous bodies; the slowest is that of silicate bodies. Of all the planets of the Solar System, known so far, Pluto takes an intermediate position. It grows slower than giant planets, but quicker than terrestrial planets.

In distant future, the planets of Solar System will increase their masses; in distant past everything was vice versa: their masses were much smaller than today. There was time when the mass of Jupiter was equal to the present-day mass of Saturn; still earlier it was even smaller. Saturn was once as big as modern Neptune, etc. The question may arise: if the Sun was much smaller in the past, then its luminosity should be much less as well and it should be too cold on Earth; but the latter contradicts the scientific data.

If, for example, the Sun mass was half of the modern value 1 billion years ago, then its luminosity was 8 times as less and any life on Earth would be impossible. But the Sun mass grows much slower: by fractions of percent during one galactic year. Rapid growth takes place only when the Solar System crosses the spiral branches of Galaxy; the last such event occurred about 4 to 5 billion years ago.

One might object then that the Solar System exists for only 4 to 5 billion years, while the Galaxy – about 18 to 20 billion years. The answer may be as follows: according to the hypothesis of the author, the Galaxy and the Solar System exist for much longer time. One of the proofs of this thesis is the pulsar having the age of 45 billion years that was discovered recently in our Galaxy by English astronomers. This, unique so far, pulsar entered the star catalogues under the name GP-1953 (Komarov. “The Universe: visible and invisible”). As to the absence of rocks of the age more than 4.5 billion years on the Earth, it could be explained by the fact that more ancient rocks of the Earth and other terrestrial planets became buried under huge thickness of cosmic sediments fallen onto the surfaces of planets during the last passage of the Solar System through a spiral branch of the Galaxy some 4 to 5 billion years ago.

If the mass of celestial bodies of the Solar System grows in the course of time, then one can, obviously, assert that so does the mass of all the other celestial bodies of the Galaxy, as well as other galaxies. But if the mass of all the stars increases, though slowly and periodically, during galactic winters, and if the celestial bodies grow mainly at the expense of diffuse matter, then the latter should have been scooped and added to the stars and other celestial bodies a long time ago, if it is not replenished by means of some mechanism.

There must be a mechanism of circulation of matter in the Universe, able to maintain the balance between the star, planet-comet and diffuse forms of matter; and such a mechanism does exist. But here, it is helpful to make a small digression again.

The fact is that there exists a circulation of matter on Earth, namely water circulation; it resembles the circulation of matter in the cosmic space.

It is known that the water of Earth hydrosphere exists in three forms or aggregative states: as liquid water, in solid state (snow, ice) and in gaseous state (steam). Water masses constantly move along the planet, being converted from one aggregative state to another. Under the influence of solar heating, water evaporates from the surfaces of seas and oceans and, being in gaseous state, rises to the upper layers of atmosphere at the height of 10 to 15 km. Here, water steam being driven by winds moves in one or another direction.

Then water steam is being condensed to the smallest water drops suspended in the atmosphere (sometimes in the form of the smallest ice or snow crystals) that, collecting into rain-clouds, sooner or later fall onto Earth surface as rain. Flowing to the oceans, water completes the cycle of its circulation; the latter can be briefly represented as: water – steam – water.

However, it is not the only form of water circulation on Earth. Together with this, double cycle of water circulation, there is also triple cycle of water circulation, during which, water goes through all the three aggregative states. Indeed, not all the clouds cease to exist falling like rain onto the Earth surface. Some of the clouds move to sub-polar regions or to the places where winter reigns that moment. As a result, precipitations fall in the form of snow; water passes into solid aggregative state.

Huge masses of snow accumulate in sub-polar regions in the course of winter. In spring, they begin to thaw; water passes into liquid aggregative state. Thus, along with double cycle of water circulation there exists the triple cycle: water – steam – snow – water. There are also other forms of water circulation, for example: water – ice – water, water – ice – steam – water, but they are of no interest for us now.

Matter in the Universe also exists in three main forms: the form of star (plasmous) substance, the form of diffuse (gas-dust) substance and the form of planet-comet (predominantly solid) substance. The substance in the Universe, like water on Earth, is not in stationary state; it is in continuous motion, in circulation turning from one form to another.

We have already known that the Sun and other stars, radiating the energy into cosmic space, lose some part of their substance; since the major part of this energy is being absorbed by diffuse matter, one may suppose that the latter increases its mass at that.

If it was not for the circulation of matter in cosmic space, then there would be no balance between the three forms of matter: star, planet-comet and diffuse. But, in such a case, one of these forms of matter would become more and more prevailing one; its proportion would constantly increase. In the long run, all the matter of the Universe would turn to one form. Substance of different galaxies would not be divided into stars, planets, their satellites, asteroids, comets and gas-dust clusters, but would consist exclusively of stars, or of gas and dust, or, finally, of invisible planet-comet bodies.

The fact that we see one and the same picture in all the visible parts of the Universe leads us to a simple conclusion that everywhere matter consists of the same forms: star, planet-comet and diffuse, though, of course, in different parts of the Universe, these form could be in different ratios. However, the larger are the parts of Universe under consideration, the less are these differences.

In order for the balance between star, planet-comet and diffuse matter to exist during many galactic years, it is necessary for any form of matter to “give” two other forms approximately the same amount of matter as it “takes” from them back. If all the stars of the Universe, taken together, begin to throw more matter to cosmic space than they get back from there, then the balance would be violated and in some, of course, very long time there would be no stars in the Universe anymore. But if so, why haven’t the stars disappeared in the course of previous billions of years?

And vice versa, if all the stars acquire more matter in the form of cosmic precipitations than they deliver to cosmic space, then the Universe would consist of stars only.

Like water on Earth, matter in the Universe has to take part in the great circulation, turning from one form to another, and so on. Like in water circulation on Earth, there may, apparently, be double and triple cycles of circulation of matter in the Universe.

However, before we consider these cycles of matter circulation, we should briefly view the mechanism of transition of cosmic substance from its one form to another.

First of all, as we have already said, any star constantly loses its substance in process of radiation. Thus, the Sun loses 1.5 * 1020 grams of substance annually at the expense of radiation; during one billion years, under constant radiation power, the Sun loses about 1.5 * 1029 grams that is equal to the mass of a giant planet. And all the stars of the Galaxy, their number being counted by hundreds of billions and maybe by trillions, during one billion years radiate the energy, the mass equivalent of which is equal to tens and hundreds millions of Sun masses.

But different stars radiate matter to interstellar space with different intensity. There are very large and hot stars that deliver several thousand times more matter to cosmic space than the Sun does. For example, Wolf-Reihe star, during 100000 years, throws about one Sun mass of substance into interstellar space. So how much matter will turn from star to diffuse form in all giant and bright stars of the Galaxy during 1 or 5 billion years? Immense amount.

However, matter is being delivered to cosmic space not only by means of radiation and outpouring. Matter is also being delivered by so-called eruptive stars, including novas and super-novas, in the form of ejections of substance, predominantly of gaseous component. From time to time, the stars are subject to flashes (explosions) of different power, at that, a star loses its gaseous layer or some part of it.

For example, a nova during flash loses the mass of a giant planet; still more is the loss of a super-nova: from several dozen percent of the Sun mass (super-nova of I type) to several Sun masses (super-nova of II type). Let’s imagine the amount of matter turning from star to diffuse form in the Galaxy in the course of flashes of all the eruptive stars during one billion years, taking into account that flashes of novas take place approximately once per 3 to 4 days, i.e. about 100 flashes a year in our Galaxy only. Flashes of super-novas are much more seldom: approximately one per 100 years in the Galaxy, but they get to interstellar space approximately as much matter as novas do: several million or even several dozen million Sun masses during one billion years.

Thus, opposite processes of matter transfer from one form to another take place. During evaporation of water from surfaces of oceans and seas of Earth, water transfers from liquid to gaseous state (steam). During flashes and radiation of stars, the star form of matter transfers to diffuse one.

In process of water steam condensation, water transfers from gaseous to liquid state and, consequently, the double cycle of water circulation (water – steam – water) takes place. In process of condensation and scooping diffuse matter in cosmic space by the stars, the reverse transition of diffuse matter to star matter occurs and, consequently, similar double cycle of circulation of matter in cosmic space (star matter – diffuse matter – star matter) takes place.

On Earth, there is also the triple cycle of water circulation: water – steam – snow – water. The same way, in cosmic space, there is the triple cycle of matter circulation: star matter – diffuse matter – planet-comet matter – star matter. At that, star matter transfers to diffuse one by means of radiation, outpouring and flashes; diffuse matter transfers to planet-comet one by means of scooping and condensation (accretion) of diffuse matter onto surfaces of celestial bodies during galactic winters.

To complete the triple cycle of circulation of matter in cosmic space, the transition of matter from planet-comet to star form is necessary. It is being carried out, first, owing to fall of “foreign” celestial bodies captured by a star into its sphere of attraction; such bodies can come from orbit of a neighbouring star or from galactic orbit or, in exceptional cases, from inter-galactic space. Second, the transition of planet-comet matter to star matter takes place by means of approaching and falling of the satellites of a star: planets, asteroids, comets and meteoric bodies onto the surface of their “master”. It happens as a result of increase of their masses and, consequently, the forces of mutual attraction, as well as owing to deceleration of celestial bodies in gas-dust environment during galactic winters. And, third, the above transition occurs by means of transformation of super-giant planets to dwarf stars in the course of expansion of the former.

Thus, similar to the triple cycle of water circulation (water – steam – snow – water) on Earth, in cosmic space, together with double cycle, there exists also triple cycle of matter circulation: star matter – diffuse matter – planet-comet matter – star matter. Owing to this never-ending circulation of matter in the Universe, that acts in the course of billions years, there exists a more or less stable proportion between different forms of matter; though, of course, in single parts of Metagalaxy, this proportion could be very different – the smaller are the parts we take for comparison, the wider these differences could be.

However, as a whole, in all the Metagalaxy, during some period of time, any form of matter “gives” the other two forms nearly the same amount of matter as it “takes” from them back.

Here, we have the same picture as for water on Earth. In different places of Earth the relationship different forms (aggregative states) of water is different, but for the planet as a whole, it is more or less stable. If the balance between different forms of water is violated for some reason, then it should restore again. For example, the balance between different aggregative states of water is violated with the beginning of a regular galactic winter, but this is a temporary phenomenon. It will be restored soon, but on a new basis: the proportion of solid water will increase. On completion of galactic winter, this new balance will be broken again, but – again – temporarily. After galactic winter, the initial or approximately initial relationship between the forms of water will be restored.

A similar phenomenon takes place in the movement of matter in the Universe. If, for some reason, the balance between different forms of matter in the Galaxy is violated (for example, as a result of a super-power explosion in the center of the Galaxy or with the beginning of metagalactic winter, when all the Galaxy rotating around the center of Metagalaxy sinks into a giant gas-dust cloud or crosses the metagalactic plane), then this balance should inevitably be restored and exist as before, though, maybe with some differences.

We have already said above that the mass of all the celestial bodies of the Solar System grows in the course of time. But it grows very non-uniformly, sometimes very slowly – during a galactic summer; sometimes quicker – with the beginning of a regular galactic winter; sometimes very quickly – when the Solar System intersects the plane of Galaxy through a spiral branch. At that, the quickest is the growth of the Sun and giant planets; slower is the growth of ice bodies; the slowest is the increase of the masses of terrestrial planets and other silicate bodies.

The growth of celestial bodies takes place, first, owing to scooping the diffuse matter by celestial bodies; second, at the expense of falling the smaller bodies onto larger bodies of the Solar System; and, third, thanks to condensation of diffuse matter. The very condensation (accretion) of diffused matter onto the surfaces of the Sun, planets and other celestial bodies is the main mechanism of the growth of masses and dimensions of celestial bodies.

In the course of rotation around the center of the Galaxy, the Solar System, like any other star-planet system, crosses the galactic plane with the intervals of 100 to 125 million years. At that, the Solar System is situated inside the compact part of gas-dust disk during 10 to 15 million years. Sometimes, once in several billion years, the Solar System crosses the plane of Galaxy through spiral branches, being as if gigantic “pipelines”, along which, gas and dust, apparently, move from the periphery of the Galaxy to its center. A great number of stars with their planets move through these spiral branches. At that, they scoop gas and dust from there. Besides, under the influence of gravitational attraction, diffuse matter begins to sink to the surfaces of stars, planets and other celestial bodies; this process is especially rapid when the speed of movement of celestial bodies is not much bigger than that of diffuse matter of spiral branches through which these bodies move.

The celestial bodies getting to the dense diffuse environment become the gravitational germs (nuclei) of condensation, these very centers, around which the condensation begins. If gas-dust clouds can, as many researchers think, condensate themselves into stars “out of nowhere” without any gravitational centers of condensation, then it would be strange to reject the idea of more rapid condensation of diffuse matter in the presence of gravitational germs of condensation, the same being stars and planets that having entered the gas-dust blobs, “ready” for concentration to stars, speed up the process of concentration of these blobs. At that, new stars may appear, however, they appear not “out of nowhere”, but originate from giant planets, on the surfaces of which, a lot of substance has been condensed.

During the passage through a spiral branch, the Solar System as if sinks into a unified, tremendous by its dimensions, though very rarefied atmosphere consisting of interstellar gas-dust matter. And this diffuse matter, under the influence of gravitational attraction, begins to fall onto the surfaces of the Sun, planets and other celestial bodies of the Solar System, the same way as the dust, being lifted to the upper layers of atmosphere of Earth or Mars by storm, falls down on completion of the latter, or as the dust, raised over the surface of the Moon as a result of meteorite strike, sinks back. At that, it may be assumed that the accretion of interstellar dust occurs quicker than that of stellar gas.

Certainly, in the course of a short period, for example, 1 year or even 100 years, the amount of gas and dust being condensed on the surfaces of celestial bodies is negligibly small. However, for 10 to 15 million years of galactic winter, the celestial bodies of the Solar System expand quite appreciably at the expense of substance captured. It’s hard to determine exactly how much is the expansion of celestial bodies of the Solar System in the course of one galactic winter. The more so that they capture the cosmic substance unequally, so that the major part falls to the share of gaseous bodies, the least part – to the share of silicate bodies. Moreover, the value of matter augmentation greatly depends on the part of spiral branch through which the Solar System passes (in the centre, away from it or past the spiral branch at all); on how long this passage lasts; on density and composition of diffuse matter in given portion of the spiral branch; on speed of movement of the Solar System relative to the diffuse matter of the spiral branch through which it moves. One might suppose, very approximately, that the mass augmentation can be from some portions of percent to some dozen percent; in some, especially “fruitful” galactic winters, the masses of celestial bodies of star-planet systems can increase (especially for gaseous bodies – stars and giant planets) several times.